RAST results ALL negative...??

TaraBeth384 · May 2012

DD first had bloody stools at 4 weeks. After failed improvement when trying elimination diets, we switched to Neocate at 4 months. Symptoms improved almost instantly, but she still has occasional eczema flare-ups, congestion, and sensitivity reactions to some new foods resulting in a severe diaper rash.

On Saturday night, she broke out in hives, had an eczema flare-up, and threw up 6 times over 24 hours. We had a party so I was thinking maybe she ate a piece of cheese or something off the floor that caused it. The only new food we gave her was kiwi, which she didn't eat much of and seems like an uncommon allergen anyway.

Because of Saturday's experience, we went ahead and did RAST testing for the Childhood Allergy Profile, which tested 10-12 allergens. All came back negative.

Has anyone had a similar experience? I can't decide if I'm relieved that we're "allergy free" or frustrated because we can't find the cause of her symptoms. I know these tests can offer false negatives, but... ugh! I was hoping for some answers!

JaredandKatie · May 2012

I'm curious to see the answers to this. As soon as we brought my daughter home from the hospital, I started suspected sensitivities/allergies; she was really fussy. Then her diapers started getting green and mucousy. At 3 weeks she started getting hives all over her body whenever I nursed her.

We did the blood test and skin prick test at 6 weeks because I wanted to continue nursing but needed to know what else to take out of my diet on top of milk and soy. I know 6 weeks was reeeeeally early, but the allergist we saw felt like it would be beneficial to test her then. Both came back negative. I'm still stumped. Her diapers are still abnormal, but the hives are gone...probably because I've eliminated most of the top 8 allergens. I'm currently milk, soy, egg, nut, wheat, and oat free. I also stay away from tomatos, avacados, and bananas because they trigger a reaction.

browneyedgoil · May 2012

i just made a simliar post but for skin testing. i guess the only response my child has is gastro/stuffiness. she won't have an anaphalaytic response which i guess is a good thing & will probably outgrow. it's extremely frustrating though b/c you never know 100% what to take out of your diet if bf'ing.

mrsmac08 · May 2012

DD has a non-IgE mediated allergy to milk (she violently vomits, and it is delayed) and DS has a non-IgE mediated allergy to soy (he vomits or spits up and it is delayed). Only IgE mediated allergies can be tested with Skin and RAST. The only way for us to test if they outgrow their allergies is to challenge them with their allergens. We believe DS may also have an IgE allergy to peanuts, though it came back negative on the skin tests...he had a reaction to pb though that included hives, so we think that was a false negative.Maybe you are dealing with something similar to our dairy and soy allergies.

mrsmac08 · May 2012

Sorry, that got cut off...or had a false negative like DS did with peanuts. Sorry you have to deal with this, good luck!

aniceucchik · May 2012

James showed all negatives on his RAST and they even tested for peas. I have a picture to prove to the Pedi that he gets hives from peas. Those hives that your DD got are definitely an allergic reaction to something. Kiwi can definitely be an allergen-esp since it has seeds in it. Jacob is mildly allergic to sesame seeds. I am going to get the skin prick on James to see if anything shows up there. So far he has had forms of soy, egg, dairy and wheat and no hives from that. He did get a mild rash on the bum area, but IDK from what.